Home | Simulations
Aspirin Titration Experiment

Chemistry | Analytical Chemistry

As Featured In

Aspirin Titration Experiment

General Aim of Aspirin Titration Experiment

Determination of acetyl salicylic acid concentration using aspirin titration experiment.

Method

Determination of concentration of the active ingredient (acetyl salicylic acid) abundant in aspirin through back acid base titration.

Learning Objectives ILO

  • By the end of aspirin Titration Online Simulation, students will:

  • Become proficient at carrying out titrations in aspirin titration lab.

  • Learn the basics of analytical procedures through online titration simulation.

  • Understand the mechanism of back acid-base titrations using aspirin assay titration.

  • Learn the function of titrations as analytical methods.

  • Get trained on the setup of titration experiments in the aspirin testing lab.

Theoretical Background

  • In the aspirin titration lab, students will analyze aspirin (acetylsalicylic acid) tablets “analgesic tablets” using the titration of aspirin experiment.Acetylsalicylic acid content will be assessed using a volumetric analysis technique.
  • Aspirin tablets contains some inactive components such as binders e.g. starch that are added to hold tablet together during formulation, disintegrating agents e.g. cyclodextrin that are added to help in tablet break down after administration, and lubricants e.g. lactose. 
  • All of these are in addition to the active component which is acetyl salicylic acid. Sodium hydroxide could react with the acetylsalicylic acid but not with the other inactive ingredients such as starch binders, etc. 
  • According to the following reaction:

C 9 H 8 O 4        +    Na OH       →     Na C 9 H 7 O 4   +    H 2 O

acetylsalicylic acid    sodium hydroxide    sodium acetylsalicylate        water

  • This is an acid-base reaction in which the acetylsalicylic acid reacts with the base sodium hydroxide to produce the salt sodium acetylsalicylate and water (acid + base → salt + water).
  • However, the aspirin titration experiment is preferably carried out as typical indirect or back titration. Standardized NaOH will be used to back titrate an aspirin solution and determine the concentration of aspirin in a typical analgesic tablet. 
  • Briefly, known excess NaOH will be added to known amount of aspirin, then the unreacted NaOH after completion of the reaction is back titrated with standardized HCl.
  • Many reactions such as reaction between acetyl salicylic acid and sodium hydroxide are slow or present unfavorable equilibria for direct titration. Since, aspirin is a weak acid, therefore, it undergoes slow hydrolysis. 
  • As shown in Figure 1, each aspirin molecule reacts with two hydroxide ions. To overcome this problem, a known excess amount of base is added to the sample solution and an HCl titration is carried out to determine the amount of unreacted base. 
  • This is subtracted from the initial amount of base to find the amount of base that actually reacted with the aspirin and hence the quantity of aspirin in the analyte.

 

Figure 1. Reaction between acetyl salicylic acid and NaOH

  • Since this is considered acid-base titration, phenolphthalein is an indicator as it changes color when all the unreacted NaOH has been reacted. 
  • This is called the “endpoint” of the reaction. The endpoint is detected when the color of phenolphthalein changes from pink to colorless.

In summary, the titration of aspirin allows accurate determination of the active ingredient in commercial tablets despite the presence of inactive components.

Principle Work of Aspirin Titration Experiment

At aspirin titration experiment:

  • Determination of concentration of the active ingredient (acetyl salicylic acid) abundant in aspirin through back acid-base titration (titration of weak acid with strong base), where excess NaOH is added to aspirin solution to neutralize acetyl salicylic acid. 
  • Then, the remaining unreacted NaOH can be back titrated against standardized HCl.
 

PraxiLabs is Recognized Worldwide

Customers Love PraxiLabs

“With the onset of the COVID-19 pandemic, we found ourselves in a situation that forced us to act quickly to find the best solution available to provide our students with a quality molecular genetics laboratory experience.”

Korri Thorlacius, B.Sc.
Biology Laboratory Instructor
Biology Department
Kwantlen Polytechnic University

'' Although there are now several vendors offering virtual reality software for physics labs, there is only one that offers a realistic, I feel like I’m in a real lab, solution: PraxiLabs.''

Dr.‌ ‌William‌ ‌H.‌ ‌Miner,‌ ‌Jr.‌ ‌
Professor‌ ‌of‌ ‌Physics‌ ‌
Palm‌ ‌Beach‌ ‌State‌ ‌College‌ ‌
Boca‌ ‌Raton,‌ ‌FL‌

" PraxiLabs offered my students a chance to actively engage with the material. Instead of watching videos on a topic, they could virtually complete labs and realize the practical applications of class topics. This is a quality alternative to in-person labs."

Crys Wright
Teaching Assistant
Texas A&M University, USA

"Great user experience and impressive interaction, I am very pleased to have tried the simulations and will continue to do so."

Dr. Khaled M Goher
Lecturer in Biomedical Engineering
Aston University, UK

The #1 Science Virtual Labs used by Educational Institutions

Explore More Interactive 3D Virtual Simulations

Designed for Safety and Engagement

Find out how PraxiLabs keeps students engaged and improves learning outcomes